This invention relates to an improved negative-resistance semiconductor device comprising complementary field-effect transistors (hereinafter referred to as FETs), and particularly concerns a unitary circuit cell of two-terminal device (as seen from outside) bearing complementary field-effect transistors in a single substrate.
Conventional negative-resistance semiconductor devices, are known in which a single-element type is realized by a physical mechanism and in which a composite type is composed of a plural number of discrete semiconductor elements wired together to form a circuit. The former type is best represented by that showing N-figured negative-resistance characteristic such as tunnel diodes, Gunn diodes, etc. and that showing S-figured negative-resistance characteristics such as thyristers, uni-junction transistors, etc. The latter type is best represented by a flip-flop circuit showing S-figure characteristics or a circuit composed of a serially connected pair of complementary field-effect transistors showing N-figured characteristics, as shown in FIG. 1.
Out of the above mentioned known devices, that showing the S-figured characteristic is in wide practical use now, but that showing the N-figured characteristic is used only for special uses. The main reason therefore is that in the conventional N-figured negative-resistance single element realized by the physical mechanism of the tunnel diode, Gunn diode, etc. of the former type, the electric current in the OFF state (or in the valley range of the N-figured characteristic) is relatively large, and hence, essentially complete cut-off of current is not realizable. Moreover, in the circuit formed by the series connection of a pair of complementary field-effect transistors of the latter type, the difficulty of integrating on tiny single-tips is a major drawback.